TRIPOLI, Lebanon — A remote control car bomb packed with ball bearings ripped through a military bus Monday, killing four soldiers and a civilian in a city that has been tormented by sectarian violence, Lebanese officials said.

It was the second deadly attack targeting troops in northern Lebanon in less than two months. Suspicion immediately fell on an al-Qaida-inspired Islamic movement that has been locked in bitter conflict with the army since last year.

The blast came two days after a car bombing in the capital of neighboring Syria killed 17 people and wounded 14. Syria said Monday that the Damascus attack used a vehicle from a neighboring Arab country it did not name.

There was nothing to suggest a link between the two attacks, although Syria has in the past blamed Islamic militants based in northern Lebanon for violence on its soil.

In Monday's attack, an explosives-laden car was parked by the road and detonated during the morning rush hour as the military bus drove by in the Bahsas neighborhood, Lebanese security officials said. Twenty-five people were reported wounded, all but three of them soldiers.

Lebanese President Michel Suleiman said later that terrorism will "not twist our arm" and only increases "our determination to confront it." A similar bombing this summer killed 18 soldiers and civilians in Tripoli.

Blaming Fatah IslamMany blamed the two attacks on Fatah Islam, a militant group that the Lebanese military battled for months last year in the Palestinian refugee camp of Nahr el-Bared, near Tripoli.

The army has received some help from the United States since the Nahr el-Bared fighting.

Suleiman, a former army chief, met last week in Washington with Defense Secretary Robert Gates, who said Lebanese armed forces were given nearly $400 million in military assistance. A further $60 million worth of aid, including helicopters, ammunition and Humvees, is awaiting Congress' approval, Suleiman's office said.

Tripoli, Lebanon's second largest city, has been rocked by sectarian fighting between anti-Syria Sunni fighters and pro-Syria gunmen of the Alawite sect, an offshoot of Shiite Islam. The clashes killed or wounded dozens this summer before a truce was reached.

A prominent criminologist, Omar Nashabeh, felt it unlikely Monday's bombing was tied to the sectarian tensions. He said Fatah Islam "most probably" was behind the attack, which he called part of "an organized campaign against the army."

Timur Goksel, a former senior official with the U.N. peacekeeping force in southern Lebanon, also speculated the blast was "a revenge attack" for Fatah Islam's defeat last year. Now a professor at the American University of Beirut, he predicted more such attacks.